Numerous industrial applications exist for a system wherein, with an assembly used for conducting a fluid from one location to another through a main fluid flow line, a conduit is provided for introducing a flushing agent into a portion of the main fluid flow line and out through the intake end thereof. Illustrative of such a system--and a system with which the invention of the present application is particularly useful--is an automatic milking system typically used on dairy farms. Such a system includes a milking claw having a plurality of teat cups, each of which is attachable to one of the teats of a cow's udder. A vacuum source is provided to effectuate milking of the cow. As milk is received in each of the teat cups, it passes through a feed line and is deposited in a main milk line for transfer to a storage tank.
A condition known as mastitis has been found to be prevalent in dairy cow herds. The condition is caused by the streptococcus hemolyticus microorganism and is transmitted from one cow in the herd to another when the milking claw of an automatic milking machine is attached to the udder of a healthy cow after having been used on a cow infected with mastitis. Consequently, the condition spreads fairly easily among the herd.
One particular strain of mastitis, although affecting the cows in a cattle herd, has no affect on humans. Consequently, when cows are infected with this strain, their milk may yet meet standards for human consumption and can be passed to the receiving and storage container for pasteurization and other processing subsequent to its collection.
Another strain can, however, cause septic sore throat in humans if the milk from an infected cow is ingested. Even when a cow is infected with this particular strain, however, it is necessary to draw milk from the cow at regular intervals. To this end, the easiest way that the milk can be drawn from the infected cow is by milking it with the automatic system at the same intervals at which healthy cows are milked.
With either strain of the microorganism, therefore, it is necessary to flush the teat cups of the milking claw prior to transfering the claw from one cow to another. Various solutions and sanitizing agents can be used for this purpose. One typical sequence of flushings would include a first phase wherein water is passed through the outermost portion of the main milk line and through the teat cups, a second phase, wherein a sanitizing agent such as an iodine solution is flushed through the outer portion of the milk line and the teat cups, and a third phase wherein water is again used as the flushing solution. Numerous phases and sequences can be utilized.
Regardless of the type of agent and sequencing of flushing used, however, it is important that sanitizing agent introduced into the outer portion of the main milk line through a conduit intersecting that line be precluded from passing through the line in a direction other than towards a milking claw. The agent can, thereby, be prevented from contaminating the milk to be used for human consumption.
The invention of the present application is apparatus for accomplishing this function. It includes positive means, responsive to the opening of the sanitizing agent conduit, for closing off the main milk line to prevent flow of the agent to the milk storage tank.